Willis Lamm's
Traffic Signal Collection

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  Marbelite "Dog House" Signal

"Dog house" is a name applied to signals that had two columns of yellow and green signals below a single red head. Dog houses are most commonly used to indicate protected left turns.

Originally, most protected left turns either involved a separate signal (drivers could only turn left on a green arrow) or a fourth signal section would display a green arrow to indicate when a left turn was protected. In the four section display, the green arrow might overlap a green ball or be a separate display. (See Old Timey Protected Left Turns.)

Over time, traffic engineers decided that a yellow display should be added to warn drivers that the protected left turn movement was ending. The addition of a yellow arrow meant that a 5-section signal was required.

Five sections produced a pretty long signal that was problematic in some span wire and mast arm configurations, so the idea came about to place the through and left turn sections side-by-side under the red section.

This particular dog house signal is interesting since the red section is actually older than the lower sections. It is a later version of the TD-19260 section, similar to the flat top except with a recessed top and drain slot. The lower sections are early type TE-19408.

Please note: To see some of the features described you may have to click on an image to bring up a larger copy in a new window. Some views were taken prior to restoration in order to show the details more clearly.

The logo parallelogram on the older head slants up
from left to right while the parallelograms on the
newer heads slant down from left to right.
Kopp No.77 "short lightning bolt" lenses.
The mounting pads for the visor screws are larger
on the newer heads to accommodate the thinner doors.
Note the different door thicknesses.
The gasket on the older head is in the housing.
The reflector has a pigtail spring on the left bottom
arm and the keeper is on the right center of the housing.
The gaskets in the newer heads are in the doors.
The reflectors have coil springs on their lower left
arms and the keepers are in front of the right arms.
Some signal notes:

The ball lenses are all Kopp No. 77 Marbelite issue lenses with the short lightning bolt and outlined "M" logo. The green arrow is a Kopp TL-1710. The yellow lens is a later model General Signals plastic lens, suggesting that the light may have originally been an older style 4-section protected left turn signal that was modified to a dog house configuration and the yellow arrow lens added some time later.

Continue to
Dog House Sequences

The lower TE-19408 sections in this Dog House were very similar to Marbelite's last signal design, produced in the 1970s.

Continue to
The Last of the Marbelites

This signal has seven-inch "tunnaway" type
visors to permit a wider angle of viewing.

Return to Marbelite Flat Top

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